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[ts-7000] Re: Cannot read PC104 from kernel space

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Subject: [ts-7000] Re: Cannot read PC104 from kernel space
From: "elliotbuller" <>
Date: Sat, 01 Dec 2007 20:04:40 -0000
Thanks for the info Frank. My PC104 daughterboard is actually a home  
brew FPGA board. If you wouldn't mind sharing the source to your hack 
that would give me something to try as I'm running out of ideas...

Regards,
-Elliot

--- In  "Frank Pagliughi" <> 
wrote:
>
> I was able to write a device driver for a proprietary PC/104
> co-processor board for use with a TS-7260, but I could never get it 
to
> work reliably with the standard speed for accessing the 104 bus. I 
had
> similar problems to what you're reporting in that individual reads 
and
> writes were sometime (often) incorrect.
> 
> Then I tried using the "fast" mode to access the board. This is a
> non-standard extension of the TS-72xx boards that clocks the bus at 
a
> faster rate (requiring a wait state setup in the EBI).  Then my 
driver
> worked fine.  But this probably wouldn't work with off-the-self 
PC/104
> peripheral boards.
> 
> I chalked it up to a problem with the default implementation of the
> PC/104 support in the boards's CPLD, but never did resolve the 
issue.
> 
> - Frank
> 
> --- In  "elliotbuller" <ebuller@> wrote:
> >
> > Is it possible I'm am accessing the PC104 memory at the wrong
> > location? Does the kernel access 16bit mem-mapped pc104 at 
0x21A00000?
> > 
> > -Elliot
> > 
> > --- In  "elliotbuller" <ebuller@> wrote:
> > >
> > > I'm having an issue reading data over the pc104 bus from a 
kernel
> > > module. I am able to read just fine from a userspace app using 
mmap.
> > > Please tell me what the difference is between the access I am 
doing in
> > > userspace and kernel space. The externel hardware generates the
> > > interrupt and I see it trap to the interrupt handler. At that 
point it
> > > tries to do a read over the bus but it is not latching the data 
right.
> > > I get random results as if I'm just reading random memory 
although I
> > > do see the mem_r line strobe low. I know you can't use mmap in a
> > > kernel module but from what I've read it sounded like the ISA 
memory
> > > region could be accessed using __ioremap(). Any suggestions 
would be
> > > great.
> > > -Elliot
> > > TS7300 - 2.4.26-ts11 #35
> > > 
> > > Here is my userspace app:
> > > 
> > > #include <unistd.h>
> > > #include <sys/mman.h>
> > > #include <stdio.h>
> > > #include <fcntl.h>
> > > #include <time.h>
> > > #include "stdtypes.h"
> > > #include "peekpoke.h"
> > > 
> > > /*
> > > Other possible bases
> > > 0x21810000
> > > 0x21A00000
> > > 0x21A10000
> > > */
> > > 
> > > #define PC104_BASE 0x21A00000L
> > > 
> > > int passed=0, failed=0, reads=0;
> > > uint16 expected=0x0;
> > > int t_delay = 0;
> > > clock_t begin, end;
> > > 
> > > delay( volatile int x )
> > > {
> > >         volatile int k=0;
> > >         while( k < x ) k++;
> > > }
> > > int main(int argc, char **argv){
> > >         uint16 reading;
> > >         volatile uint16 *start;
> > >         long seconds;
> > >         uint32 count = 0;
> > >         int fd = open("/dev/mem", O_RDWR|O_SYNC);
> > >         start = mmap(0, getpagesize(), PROT_READ|PROT_WRITE,
> MAP_SHARED,
> > > 
> > >           reading =  PEEK16((long)start);
> > >           expected = reading + 1;
> > > 
> > >           while(count < 10000000)
> > >           {
> > >                 reading =  PEEK16((long)start);
> > >                 if(reading == expected)
> > >                 {
> > >                   passed++;
> > >                   expected++;
> > >                 }
> > >                 else
> > >                 {
> > >                   failed++;
> > >                   expected=reading+1;
> > >                 }
> > >                 count++;
> > >           }
> > >           printf("%d READS\n---------\nPASSED: %d   FAILED: %
d\n",
> > > count, passed, failed);
> > >         
> > >         close(fd);
> > >         return 0;
> > > }
> > > 
> > > /***********************************/
> > > 
> > > Here is my kernel module:
> > > // Linux Device Driver Template/Skeleton
> > > // Kernel Module
> > > 
> > > #include <linux/module.h>
> > > #include <linux/errno.h>
> > > #include <linux/fs.h>
> > > #include <linux/mm.h>
> > > #include <linux/interrupt.h>
> > > #include <linux/sched.h>
> > > #include <linux/init.h>
> > > #include <linux/ioport.h>
> > > 
> > > #include <asm/uaccess.h>
> > > #include <asm/io.h>
> > > #include "peekpoke.h"
> > > 
> > > #define PC104_MAJOR              63
> > > #define PC104_NAME               "PC104"
> > > #define PC104_INTERRUPT          22        // Corresponds to 
IRQ5
> > > #define PC104_BASE               0x21A00000L
> > > #define PC104_MEM_SIZE           4
> > > 
> > > 
> > > MODULE_AUTHOR("Elliot Buller: Colorado State 2007");
> > > MODULE_LICENSE("GPL");
> > > MODULE_DESCRIPTION("PC104 Data Acquisition Card Driver");
> > > 
> > > extern void disable_irq (unsigned int irq);
> > > static unsigned int counter = 0;
> > > static int interruptcount = 0;
> > > static volatile uint16_t *base;
> > > static char string[150];
> > > DECLARE_WAIT_QUEUE_HEAD(pc104_wait);
> > > static int data_not_ready = 1;
> > > 
> > > static int pc104_open (struct inode *inode, struct file *file) {
> > >   printk("pc104_open\n");
> > >   return 0;
> > > }
> > > 
> > > static int pc104_release (struct inode *inode, struct file 
*file) {
> > >   printk("pc104_release\n");
> > >   return 0;
> > > }
> > > 
> > > static ssize_t pc104_read (struct file *file, char *buf,
> > >                      size_t count, loff_t *ppos) {
> > >   int len, err;
> > >   
> > >   // check if we have data - if not, sleep
> > >   // wake up in interrupt_handler
> > >   while (data_not_ready) {
> > >     interruptible_sleep_on(&pc104_wait);
> > >   }
> > >   data_not_ready = 1;
> > > 
> > >   /* Add read code here */
> > >   return len;
> > > }
> > > 
> > > // write function called when to /dev/skeleton is written
> > > static ssize_t pc104_write (struct file *file, const char *buf,
> > >                       size_t count, loff_t *ppos) {
> > >   int err;
> > >   err = copy_from_user(string,buf,count);
> > >   if (err != 0)
> > >     return -EFAULT;
> > >   counter += count;
> > >   return count;
> > > }
> > > 
> > > 
> > > // interrupt handler
> > > static int interrupt_handler(void)
> > > {
> > >   
> > >   interruptcount++;
> > >   printk(">>> PC104 BUS INT: interruptcount=%d\n", 
interruptcount);  
> > >  
> > >   printk("PC104 Samples: 0x%04X\n", PEEK16(base));
> > > 
> > >   /* Data ready. Wake up userspace process */
> > >   data_not_ready = 0;
> > >   wake_up_interruptible(&pc104_wait);
> > >   
> > >   return IRQ_HANDLED;
> > > }
> > > 
> > > // define which file operations are supported
> > > struct file_operations pc104_fops = {
> > >   .owner  =       THIS_MODULE,
> > >   .llseek =       NULL,
> > >   .read   =       pc104_read,
> > >   .write  =       pc104_write,
> > >   .readdir =      NULL,
> > >   .poll =         NULL,
> > >   .ioctl  =       NULL,
> > >   .mmap  =        NULL,
> > >   .open =         pc104_open,
> > >   .flush  =       NULL,
> > >   .release =      pc104_release,
> > >   .fsync  =       NULL,
> > >   .fasync =       NULL,
> > >   .lock  =        NULL,
> > >   .readv  =       NULL,
> > >   .writev =       NULL,
> > > };
> > > 
> > > // initialize module (and interrupt)
> > > static int pc104_init_module (void) {
> > >   int i;
> > >   int ret;
> > >   printk("<1>Initializing PC104 module\n");
> > >   
> > >   i = register_chrdev (PC104_MAJOR, PC104_NAME, &pc104_fops);
> > >   if (i != 0) return - EIO;
> > >   
> > >   // INIT INTERRUPT
> > >   ret = request_irq(PC104_INTERRUPT, &interrupt_handler,
> > >               SA_INTERRUPT, "pc104_driver", NULL);
> > >   
> > >   /* Check to see if ISA memory in use */
> > >   if (check_mem_region(PC104_BASE, PC104_MEM_SIZE)) {
> > >     printk("pc104: memory already in use\n");
> > >     return -EBUSY;
> > >   }
> > >   
> > >   /* Request memory space */
> > >   request_mem_region(PC104_BASE, PC104_MEM_SIZE, PC104_NAME);
> > >   
> > >   /* Warning: Cannot use ioremap as it adds offset */
> > >   base = (volatile uint16_t*)__ioremap(PC104_BASE, 
PC104_MEM_SIZE, 0);
> > >   if(base == NULL)
> > >   {
> > >     printk("Error mapping memory!\n");
> > >     return -EBUSY;
> > >   }
> > >   
> > >   printk("Memory mapped: 0x%08X\n", base);
> > >   return 0;
> > > }
> > > 
> > > 
> > > // close and cleanup module
> > > static void pc104_cleanup_module (void) {
> > >   printk("<1>Cleaning up PC104 module\n");
> > >   
> > >   iounmap((void*)base);
> > >   release_mem_region(base, PC104_MEM_SIZE);
> > >   unregister_chrdev (PC104_MAJOR, PC104_NAME);
> > >   disable_irq(PC104_INTERRUPT);
> > >   free_irq(PC104_INTERRUPT, NULL);
> > >   
> > > }
> > > 
> > > module_init(pc104_init_module);
> > > module_exit(pc104_cleanup_module);
> > >
> >
>




 
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